Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jan. 01, 2020	Dec. 31, 2018
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Allowance for Unfunded Commitments	$ 64,776		$ 64,776		$ 21,907
Expense Related to Qualified Affordable Housing Projects	6,000	$ 5,000	12,000	$ 10,000
Remaining Investment in Qualified Affordable Housing Projects	262,000		262,000		234,000
Variable Interest Entity Reporting Entity Involvement Unfunded Obligation Amount	136,000		136,000		123,000
Qualified Affordable Housing Investments, Impairment Loss			0		0
Loans Repurchased Under Make Whole Requests	3,000		$ 3,000		$ 2,000
Loans Sold To Outside Investors Loss ReimbursementSettlement Paid			no		negligible
Loans Sold To Outside Investors Original Amount	13,500,000		$ 13,500,000
Loans Sold To Outside Investors Remaining Outstanding Amount	7,400,000		7,400,000
Unfunded Commitments	64,776		64,776		$ 21,907
Residential Mortgage Loans Sold With Recourse Risk	34,000		34,000		39,000
Residential Mortgage Loans Sold With Credit Recourse Risk	39,000		39,000		45,000
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Provision for unfunded commitments			24,000		(2,500)
Unfunded Commitments					21,907		$ 24,336
Mortgage Repurchase Reserve
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Unfunded Commitments	1,000		1,000		795
UnconsolidatedProjectsLowIncomeHousing [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	274,000		274,000		248,000
PrincipalInvestmentCommitment [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	$ 28,000		$ 28,000		$ 26,000
Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Allowance for Unfunded Commitments						$ 18,690